Actually, I DO! My challenges are for the individual client to challenge him or herself. I play games with my clients from time to time to keep them challenged and to keep things interesting. During a training session, I may spring a “challenge” on them in which if they WIN, they get an “immunity” from something else that they might not like (I conduct these challenges very much like the reality show “Survivor,” including even having created an immunity idol for them!). It’s a lot of fun for them and me!
When I was in the corporate wellness arena as Fitness Director, I definitely did introduce periodic challenges for the members there as a way to increase their consistency in exercise.